1. Field of the Invention
The present invention relates to a header tank for a heat exchanger such as a condenser or the like used in an air conditioner of a motor vehicle or the like.
2. Description of the Related Art
FIGS. 1 and 2 show a conventional heat exchanger (condenser) used in an air conditioner (Japanese Patent Application Laid-open No. H7-027496). As shown in FIG. 1, a condenser 1 is comprised of a pair of head tanks 11 and 12 opposing to each other, a plurality of flat tubes 13 arranged between the header tanks 11 and 12, and corrugated fins 14 interposed between the flat tubes 13 and 13.
Each of the header tanks 11 and 12 is comprised of a pipe 15, closing members 16 closing both end opening portions of the pipe 15, and partition plates 17 sectioning a passage extending in a longitudinal direction within the pipe 15. In this embodiment, the closing member 16 doubles as a joint with an outlet pipe or an inlet pipe.
As shown in FIGS. 1 and 2, a lot of tube insertion holes 18 for inserting the tubes 13 are formed according to a press molding in the pipes 15 constituting the header tanks 11 and 12.
The structure is made such as to prevent a cooling medium from leaking from the insertion hole 18 by fixing the tube 13, a periphery of the insertion hole 18 and the fin 14 according to a brazing after inserting the tube 13 to the tube insertion hole 18.
Within the condenser 1, the cooling medium flows within the tube 13 so as to meander between one header tank 11 sectioned by the partition plate 17 and another header tank 12.
The cooling medium is cooled by radiating heat to an air ventilating through a gap of the fins 14 between the tubes 13. Accordingly, the cooling medium introduced into the condenser 1 in a gas phase state is flow out in a liquid phase state from the condenser 1.
FIG. 3 is an exploded perspective view of the pipe 15, and FIGS. 4A and 4B are cross sectional views of the pipe 15.
As shown in FIGS. 3, 4A and 4B, the pipe 15 in the conventional header tanks 11 and 12 is comprised of combining two semi-cylindrical separated bodies 19 and 20. A cross sectional shape of each of the separated bodies 19 and 20 is formed in a semicircular shape. An approximately L-shaped receiving portion 19a is formed in one separated body 19 constituting the pipe 15 for the purpose of being brought into contact with an opening peripheral edge portion 20a of another separated body 20 so as to position.
However, in the conventional header tanks 11 and 12 for the heat exchanger, since the pipe 15 is formed in the cylindrical shape as shown in FIG. 4B, an inserting depth L1 of the tube 13 is large, and it is hard to secure a passage cross sectional area S of the pipe 15 in a state in which the tube 13 is inserted.
Therefore, in order to make the passage cross sectional area S of the pipe 15 large, it is necessary to make a diameter of the pipe 15 large, so that the pipe 15 is enlarged. On the other hand, in the case that the diameter of the pipe 15 is made small for the purpose of making the condenser 1 compact, there is a problem that the passage cross sectional area S of the pipe 15 can not be sufficiently secured.
The present invention is made for the purpose of solving the problem mentioned above, and an object of the present invention is to provide a header tank which can make a heat exchanger (a condenser) small while securing a passage cross sectional area of a pipe.